Appliance and method for tempering a plurality of process items by absorption of electromagnetic radiation generated by plural sources of the radiation

ABSTRACT

An appliance for the simultaneous tempering and processing of a plurality of process items with the aid of electromagnetic radiation. The appliance is a stack oven, the process items and the energy sources being arranged on one another in such a way that a process item is present between two energy sources and an energy source is present between two process items. The appliance is particularly suitable for tempering the process items in the presence of a process gas. Using the appliance, a variable heating and cooling profile with variable process parameters is possible. In particular, reliable tempering of a process item in the form of a large-area multilayer body with layers of different physical properties is possible.

BACKGROUND OF THE INVENTION

The invention relates to an appliance for tempering a process item. Suchan appliance is known, for example, from EP 0 662 247 B1. In addition tothe appliance, a method for tempering a process item is presented.

The process item known from EP 0 662 247 B1 is a multilayer body whichis manufactured by applying a functional layer to a substrate. In orderthat the functional layer and/or the substrate may exhibit a desiredphysical (electrical, mechanical, etc) and/or chemical property, aprocess is carried out on the process item or the layer and/or thesubstrate. The processing includes tempering the process item in thepresence of a gas (process gas).

For tempering, the process item is arranged in a closed graphitetempering container. During the tempering process, the process item isexposed to a process gas with gaseous selenium. During the temperingprocess, the process item accepts a quantity of energy, a partialquantity of the quantity of energy being supplied to each layer. Thetempering process takes place with, for example, a heating rate of 10°C. per second. A halogen lamp is used as the energy source of thequantity of energy. By means of the halogen lamp, the graphite temperingcontainer is radiated by an electromagnetic radiation and the temperingcontainer is heated by this means. Graphite exhibits a high absorptioncapability for the electromagnetic radiation in the spectral range ofthe halogen lamp. The quantity of energy absorbed by the graphite issupplied by thermal radiation and/or thermal conduction to the processitem. The tempering container therefore functions as a secondary energysource or as an energy transmitter.

Graphite exhibits a high emission capability and a high thermalconductivity. When the process item is laid on the bottom of thetempering container, the supply of the energy quantity to a lowersurface of the process item takes place, essentially, by thermalconduction. A quantity of energy is supplied to an upper surface of theprocess item by thermal radiation, thermal conductivity and convection.

The larger the process item (larger surface), the more different thematerials used in the process item (for example strongly differingthermal expansion coefficient, differing absorption capability for thequantity of energy, etc) and the higher the tempering rate is (heatingrate, cooling rate), the more difficult it is to control a temperaturehomogeneity or temperature inhomogeneity in the process item. Thetemperature inhomogeneity can lead to a mechanical stress in the processitem and, therefore, to destruction of the process item. For thisreason, the known appliance with the tempering container mainly suitablefor tempering a single process item.

SUMMARY OF THE INVENTION

The object of the invention is to demonstrate how, using a singleappliance, a plurality of process items can be simultaneously temperedwhile controlling a temperature homogeneity or temperature inhomogeneityin each of the process items.

In order to achieve the object, an appliance is specified for temperinga plurality of process items in a certain gas atmosphere by acceptanceof a quantity of energy by a process item by means of absorption of acertain electromagnetic radiation and by acceptance of at least afurther quantity of energy by at least one further process item by meansof absorption of at least a further certain electromagnetic radiation.The appliance exhibits at least one device for producing the gasatmosphere, a tempering unit with at least one energy source forgenerating the electromagnetic radiation and at least one furthertempering unit with at least one further energy source for generatingthe further electromagnetic radiation. The tempering unit and thefurther tempering unit are arranged relative to one another to form atempering stack in such a way hat the process item can be arranged in acertain stacking direction of the tempering stack between the energysource and the further energy source and the further energy source canbe arranged between the process item and the further process item.

The energy source is, for example, a heater plane, which is formed by aheater array. The heater array consists, for example, of rod-shapedhalogen lamps or heating rods arranged parallel to one another. Theprocess items are, for example, arranged between the heater planes inthe tempering stack. Such an arrangement makes the applianceparticularly suitable for the simultaneous tempering of a plurality ofprocess items. The tempering units can be arranged both vertically andhorizontally. At least one energy source is associated with each processitem, the process item being arranged during tempering in the radiationfield of the respective electromagnetic radiation. In order to acceptthe respective quantity of energy, the process items exhibit acorresponding absorption of the electromagnetic radiation. Thearrangement ensures that each process item is provided with an energydensity necessary for the tempering process. Mutual shadowing of theprocess items in the stack and, therefore, an uneven radiation of theprocess items due to the electromagnetic radiations does not occur. The(adjustable) gas atmosphere is, for example, characterized by a definedpartial pressure of a gas or gas mixture (for example air). It is alsoconceivable for the gas atmosphere to be a vacuum.

In a particular embodiment, at least one of the tempering units exhibitsat least one additional energy source for generating an additionalquantity of energy and for accepting the additional quantity of energyby the process item of the tempering unit. The additional energy sourcemakes it possible to take account of a different infrared absorption bythe front surface and the rear surface of the process item and, by thismeans, to contribute to improving temperature homogeneity of the processitem during the tempering process. In addition, an increase in theheating rate can be achieved by means of the additional energy source.

The acceptance of the additional quantity of energy can, essentially,take place by thermal conduction, thermal radiation and/or convection.In the case of thermal conduction, the process body is in contact withthe energy source. Thermal radiation is at least partially absorbed bythe process item and the process container in accordance with theirabsorption spectra within the spectral range of the heating element. Inthe case of convection, a gas for example, which can also be the processgas, is led past the process body. In this process, a quantity of energycan be exchanged between the gas and the process body.

In a particular embodiment, the additional energy source is an energysource for generating an additional electromagnetic radiation and theacceptance of the additional quantity of energy is an absorption of theadditional electromagnetic radiation. In a further embodiment, theprocess item of the tempering unit is arranged between the energy sourceof the tempering unit and the additional energy source of the temperingunit. This makes it possible to heat different surfaces of the processitem, for example an upper surface and a lower surface of a flat processitem, differently. This is particularly advantageous when the processitem is a multilayer body which exhibits layers of different material.The layers exhibit, for example, a different absorption capability forthe electromagnetic radiation of the energy sources at the same thermalexpansion coefficient. In order to avoid a temperature inhomogeneity inthe thickness direction of the multilayer body, the layers are, forexample, radiated with an electromagnetic radiation of different energydensity (energy per unit area).

In a particular embodiment, the energy source, the further energy sourceand/or the additional energy source can be triggered independently ofone another. The quantity of energy which is supplied to the processitems or different layers of the process items can be individuallyadjusted or regulated. As an example, two adjacent tempering units areoptically separated from one another, i.e. so that electromagneticradiation of one tempering unit does not radiate into the adjacenttempering unit. This is, for example, achieved by a body, which isopaque or partially transparent to the electromagnetic radiation,between the tempering units. This body is, for example, a reflectionbody (see below). The process item is located between the energy sourceand the additional energy source so that, in addition, only these energysources contribute to the tempering of the process item. The quantitiesof energy, which are supplied to the process item in the form of “upperheat” and “lower heat”, can be adjusted individually in this way for theindividual layers of the individual process item.

In a particular embodiment, the electromagnetic radiation, the furtherelectromagnetic radiation and/or the additional electromagneticradiation is infrared radiation (thermal radiation). An energy source ofa thermal radiation with an intensity maximum at a wavelength of between1 micron and 2 microns is conceivable. Such a heat source is, forexample, a halogen lamp. Also conceivable is an energy source in theform of a resistance heating element which emits the thermal radiation.Such an element exhibits, for example, graphite, silicon carbide and/ora metal alloy such as nickel-chromium. Additionally conceivable is anyelectromagnetic radiation (microwaves, ultraviolet light) which can leadto heating of the process item.

In a particular embodiment, at least one of the tempering units exhibitsat least one reflection body for forming a radiation field of at leastone of the electromagnetic radiations. A flux density of anelectromagnetic radiation onto a process item is controlled by thereflection body. In this process, the flux density is concentrated onthe process item. The reflection body exhibits, for example, a materialwhich at East partially reflects the electromagnetic radiation of theenergy source. The reflection body can be arranged in such a that areflected electromagnetic radiation is directed onto a process item. Thereflection body of the tempering unit is, for example, arranged towardan adjacent tempering unit. In this way, the reflection body is locatedquasi between two tempering units. It is also conceivable for thereflection body to be arranged directly at an energy source. In thisway, it is possible to adjust a certain opening angle, for example, ofthe radiation field electromagnetic radiation.

The reflection body can be opaque or almost opaque to theelectromagnetic radiation of the energy source. For this purpose, thereflection body exhibits, for example, a high reflection capability witha simultaneous low transmission capability. In particular, thereflection body is partially permeable to at least one of theelectromagnetic radiations. This is advantageous when each of thetempering units has respectively available only one energy source, forexample in the form of a heater plane. Because of the reflection body,the electromagnetic radiation of a tempering unit reaches into anadjacent tempering unit and can, therefore, contribute to tempering theprocess item of the adjacent tempering unit. Material and thickness ofthe reflection body are selected in such a way that a transmissionspectrum and reflection spectrum is located in the range of thewavelength of the electromagnetic radiation of the associated energysource. In this case, the absorption capability and emission capabilityof the process item is likewise taken into account. Transmissioncapability and reflection capability of the reflection body andabsorption capability and emission capability of different sides of theprocess item are matched to one another in such a way that nounallowable temperature gradient in the process item (for example in thethickness direction of the process item) occurs during the temperingprocess. The temperature homogeneity is ensured during the temperingprocess. The material of the reflection body is selected in such a waythat an optical property, such as the absorption capability or thereflection capability of the reflection body, remains essentiallyconstant during the tempering process. Conventional reflective materialscan be considered as the reflection body to suit the desired reflectionspectrum. The reflection body is advantageously in ceramic, or in fusedquartz. These materials are inert with respect to a number of processgases. The reflection body can also be a reflecting, chemically lessactive coating such as barium sulfate or aluminum oxide on a substratein glass ceramic or quartz glass. It is, for example, also conceivablefor a halogen lamp sleeve to exhibit the coating. Also conceivable is areflection body with a metal coating.

In a further embodiment of the invention, at least one of the temperingunits exhibits at least one means for cooling the process item.Associated with this is the advantage that a process procedurecomprising various method steps with at least one heating phase andcooling phase can be carried out with the aid of the same appliance. Themeans for cooling is, in particular, a cooling gas and/or a coolingfluid. The cooling with the aid of the cooling gas takes place byconvection, a cooling gas, which is cooler in comparison with theprocess item, for example, being led past the process item. The coolingcan also take place by thermal conduction, the process item being incontact with a cooling body with a corresponding thermal conductivitycoefficient. It is conceivable for the cooling body to be an envelope ofthe tempering unit and/or of the tempering stack, with a hollow spacethrough which the cooling gas or the cooling fluid can be led.

In a further embodiment, at least one of the energy sources is arrangedin an envelope, which is at least partially transparent to theelectromagnetic radiation of the energy source. The envelope consists,for example, of quartz glass. The envelope is preferably vacuum-tight.The energy source can be protected from contact with a process gas bymeans of the envelope. A further advantage of this embodiment is simplechanging of the energy source.

In a particular embodiment, the envelope of the energy source exhibitsan optical filter for the electromagnetic radiation of the energysource. In this way, deliberate influence can be taken on the opticalproperty (absorption capability and transmission capability) of theenvelope.

In a particular embodiment, the envelope of the energy source exhibitsmeans for cooling. In this arrangement, the means for cooling is, inparticular, arranged in the envelope of the energy source. In this case,for example, not only the process item but also the energy source iscooled. This leads to a rapid reduction of an energy density radiatedfrom the energy source and, therefore, to an efficient cooling of theprocess item. Particularly when high energy densities and/or hightemperature homogeneity are required, the energy sources, in particularhalogen lamps, are arranged at only a small distance from the processitem so that, in addition to a high radiation intensity, a high level ofcooling performance is also available. In the case of larger distancesbetween the energy sources, additional cooling elements can be arrangedbetween the energy sources in the case of high demands for coolingperformance. Such a cooling element is, for example, a tube throughwhich a cooling gas or a cooling fluid is led. A covering of theenvelope, through which the cooling fluid flows for cooling purposes,is, for example, conceivable. Also conceivable is a combination ofcooling gas and cooling fluid. In order to avoid a temperature shock, acooling gas can be initially led through the intermediate space betweencovering and energy source. In a further step, the cooling fluid ispumped through the covering for efficient cooling. In a furtherembodiment, the envelope of the energy source exhibits the reflectionbody. In this case, the reflection body is, in particular, arranged inthe envelope of the energy source. In this way, there is no sort oflimitation with respect to the reactivity of the material of thereflection body relative to a process gas. The only decisive featuresare the optical properties of the reflection body.

In a further embodiment, the envelope of the energy source exhibits anoptical filter for the thermal radiation of the energy source. in thiscase, the optical filter is, in particular, arranged in the envelope ofthe energy source. In this way, there is no sort of limitation withrespect to the reactivity of the material of the optical filter relativeto a process gas. The only decisive features are the optical propertiesof the filter. The optical filter can then be selected in such a waythat the desired spectrum of the energy source is achieved.

In a particular embodiment, at least one of the tempering units exhibitsa tempering container, exhibiting a container wall, for holding theprocess item of the tempering unit. In this case, the tempering unit isused to arrange the process item in the radiation field of one of theelectromagnetic radiations. It is conceivable for the container wallitself to exhibit the energy source of the electromagnetic radiation.The wall is, for example, graphite, through which electrical currentflows during the tempering process.

It can be particularly advantageous for a container wall, whichfunctions as a support surface for the process item, to permit a releaseof the energy quantity to the process item by means of thermalconduction. For this purpose, the container wall exhibits acorresponding thermal conductivity. This is particularly advantageouswhen the process item exhibits a low absorption in the spectrum of theenergy sources. The support surface then consists of a material whichexhibits a high absorption in the spectrum of the energy source.

In a further embodiment, the tempering stack exhibits a stack body witha body wall. The stack body is, for example, used as a holding devicefor the tempering units and/or as a reflection body for the thermalradiation and/or as enveloping insulation body of the tempering stack.In a particular embodiment, the stack body can be tempered. A temperingrate of the process item can be additionally influenced by this means.The stack body is, for example, a frame with an insertion plane or aninsertion rail for, in each case, a tempering unit, an energy source, aprocess item and/or a support surface of a process item.

The stack body advantageously exhibits a hollow space, which can beevacuated and can be filled with the process gas. In this case, thetempering units are arranged relative to the tempering stack in thishollow space. It is also conceivable for a body wall of the stack bodyto exhibit the container wall of the tempering container. In this way,the stack body can, for example, be essentially formed by the containerwalls of the tempering container. The tempering containers are stackedone above the other to form the stack body. In this case, the temperingcontainers can be designed, with the aid of holes and recesses, in sucha way that a common hollow space of the tempering containers is present.

By means of the stack body, which can be evacuated and can be filledwith the process gas, a common process gas atmosphere for all theprocess items arranged in the tempering containers can be created. Thisembodiment can be advantageous when a large quantity of process gas isnecessary at the smallest possible gas flow.

In a further embodiment, the tempering stack and/or the stack body arearranged in a tempering chamber with a chamber wall. In a furtherembodiment, the tempering chamber can be evacuated and can be filledwith the process gas. The tempering chamber has available, for example,a door which can be closed and through which the tempering containers,which are located in the tempering chamber, can be loaded with theprocess items. It is also conceivable that the stack body can beinserted into the tempering chamber through the door. A tempering unitcan likewise be directly pushed into a tempering chamber on anappropriate rail. The tempering chamber functions as holding device forthe tempering units.

The tempering chamber is, in particular, provided with a vacuum-tightdoor, on which, within the tempering chamber, a door of the stack bodyis arranged, which door can be opened and closed independently of thedoor of the tempering chamber. In this way, the gas atmosphere in thestack body and also in the tempering containers can be easily controlledwithout the tempering chamber having to be opened.

The tempering chamber and/or the stack body can, in particular, betempered. This is particularly advantageous when a processing eductand/or product condenses during tempering on a surface of the stack bodyand/or of the tempering chamber. A gas pressure within the temperingchamber can, in addition, be controlled. In order to increase a powerdensity of the respective electromagnetic radiation, the stack bodyand/or the tempering chamber can exhibit a reflection body or areflection coating.

In a particular embodiment of the invention, the container wall, thebody wall and/or the chamber wall exhibit the device for producing thegas atmosphere. The device is, in particular, a gas opening for at leastone gas for evacuating and/or filling the tempering container, the stackbody and/or the tempering chamber with the gas. The gas is, inparticular, a process gas and/or a scavenging gas. All conceivablecorrosive and non-corrosive gases can be considered as the process gas.Examples for this are oxidizing gases such as oxygen or a molecularhalogen and reducing gases such as hydrogen, hydrogen sulfide, hydrogenselenide, doping gases or the like. It is, for example, conceivable fora first process gas to be necessary during the tempering process in afirsttempering stage whereas a further process gas is necessary during afurther tempering stage. It is also conceivable for the process gas tohave to be topped up within a tempering stage. Nitrogen or another inertgas can be considered as the scavenging gas. It is used for cleaning thetempering container, the stack body and/or the tempering chamber. Inaddition, vacuum can be applied for the cleaning and/or for theprocessing or tempering.

In a further embodiment, the process item and the further process itemare in contact with one another through the gas opening. As an example,a gas outlet of the tempering chamber is connected to a gas inlet of afurther tempering container. This produces a common gas atmosphere inthe two tempering containers. Both process items can, for example, bebrought into contact with the same gas flow. It is, however, alsopossible for each tempering container to be provided with its own gasinlet and gas outlet.

The possibility of evacuating and for filling the tempering container,the stack body and or the tempering chamber is particularly advantageouswhere a toxic and/or corrosive process gas is used. Last but not least,an inspection of the respective process gas atmosphere and cleaning ofthe container is important for safety reasons when such gases are used.

In a further embodiment, at least one of the process items is amultilayer body with at least one layer which exhibits a certainabsorption of at least one of the electromagnetic radiations.

In a particular embodiment, at least one of the tempering units exhibitsat least one transparent body, which exhibits a certain absorption and acertain transmission for at least one of the electromagnetic radiationsand which is arranged in the radiation field of the electromagneticradiation between the energy source of the electromagnetic radiation andone of the process items. The particular advantage of the transparentbody, in particular when tempering a multilayer body, is dealt withfurther below in association with the tempering unit embodiment.

In a particular embodiment, the envelope of the energy source, thetempering container, the stack body, the tempering chamber, thetransparent body and/or the reflection body exhibit a material which isinert with respect to the gas. The material is, in particular, from thegroup of glass, quartz glass, fused quartz, ceramic, glass ceramicand/or metal. These materials are inert with respect to a number ofprocess gases, i.e. they are less active. In addition, some materialssuch as quartz glass or glass ceramic have a low thermal expansioncoefficient. This is particularly important in the case of an appliancewhich is composed of constituent parts in different materials. Adimension of a constituent part can change within a permissibletolerance. This ensures that the appliance is not destroyed because of amechanical stress during the tempering process, i.e. it is kept. Inaddition, this facilitates an inspection of a gas atmosphere. A possiblegap in a constituent part or between the constituent parts of theappliance scarcely changes during the tempering process because of thelow thermal expansion coefficients of its constituent parts. Anadditional advantage is provided by the use of a material which can bemachined (for example ceramic or glass ceramic which can be machined orfused quartz which can be machined).

The way in which various embodiments of the tempering unit ensure thatlarge-area process items, in particular multilayer bodies with anasymmetrical layer sequence, can be tempered while controllingatemperature homogeneity of the process item is described below.

The process item of the tempering unit is, for example, a multilayerbody which exhibits a first layer and at least a second layer. Thetempering takes place by the multilayer body accepting a quantity ofenergy with the first layer accepting a first partial quantity of thequantity of energy and the second layer accepting a second partialquantity of the quantity of energy. The tempering unit, which exhibitsat least one energy source for the quantity of energy, is wherein thefirst layer is arranged between a first energy source and the secondlayer and the second layer is arranged between a second energy sourceand the first layer. At least one of the energy sources exhibits anemission of a certain electromagnetic radiation with a radiation fieldand at least one of the layers exhibits a certain absorption for thiselectromagnetic radiation and is arranged in the radiation field. Inaddition, at least one transparent body, which exhibits a certaintransmission and a certain absorption for the electromagnetic radiation,is arranged in the radiation field between the energy source with theradiation field and the layer, which exhibits the absorption of theelectromagnetic radiation and which is arranged in the radiation field.

The transparent body makes it possible to heat the layers of themultilayer body individually, i.e. to specifically control, to regulateand/or to adjust in advance the partial quantity of the quantity ofenergy which a layer accepts. A quantity of energy is, for example,determined with the aid of a control circuit during the temperingprocess (see below). It is also conceivable for an adjustment in advanceof the energy sources (for example energy density, type of energy, etc)to be sufficient without an additional control circuit. An individualheating of the layers of the multilayer body is also possible in thecase of very high heating rates of between 1° C. per second and, forexample, 100° C. per second and above. The individual heating makes itpossible to keep the mechanical stresses—and a deformation of themultilayer body occurring, under certain circumstances, because of it—assmall as possible during the tempering process.

The basis for this is the transparent body which is, optically,partially permeable (semi-transparent). Due to the transmission which,for example, lies at a certain wavelength between 0.1 and 0.9, theelectromagnetic radiation described above passes through the transparentbody onto a layer. The layer can accept a corresponding quantity ofenergy or partial quantity of the quantity of energy, which is emitteddirectly from the energy source.

The transparent body also exhibits a certain absorption for theelectromagnetic radiation. The energy absorbed in this way can berejected to the surroundings in the form of thermal radiation and/orthermal conduction. In a particular embodiment, the appliance fortempering a multilayer body has a transparent body available which, dueto the absorption of the electromagnetic radiation, exhibits a thermalradiation and/or thermal conduction in the direction of the multilayerbody. This makes it possible to temper a layer by thermal radiationand/or thermal conduction. It is also conceivable for a first layer ofthe multilayer body, which exhibits transmission for the thermalradiation, to be tempered, essentially, by thermal conduction onlywhereas a second layer of the same multilayer body can be essentiallytempered by the thermal radiation of the same transparent body. A firstlayer with corresponding transmission is, for example, a glass layer.When an electromagnetic radiation of an energy source and/or atransparent body meets the glass body, a small proportion of theradiation(approximately 4%) is reflected. The major proportion (morethan 90%) passes more or less unhindered through the glass and thenmeets a second layer of the multilayer body. This radiation can beabsorbed there and leads to an acceptance of a quantity of energy bythis second layer. The glass layer cannot be tempered sufficientlyrapidly by radiation or thermal radiation at a very high heating rate.On the other hand, a relatively rapid tempering is possible by thermalconduction if the transparent body can accept a partial quantity of thequantity of energy and transfer it to the glass layer.

The case where the transparent body is itself a layer of the multilayerbody is also conceivable. The transparent body can accept a partialquantity of the quantity of energy by absorption of a part of theelectromagnetic radiation and, by transmission, permit a further partialquantity of the quantity of energy to pass through for acceptance by afurther layer.

In a particular embodiment of the tempering unit, a layer of themultilayer body is a substrate for at least one further layer of themultilayer body. The multilayer body exhibits, in particular, anasymmetric layer sequence. The multilayer body consists, for example, ofa substrate coated on one side. Individual layers of the multilayer bodycan also be arranged adjacent to one another.

In a particular embodiment, a layer of the multilayer body exhibits amaterial which is selected from the group of glass, glass ceramic,ceramic, metal and/or plastic. Temperature-resistant plastic such asTeflon can, in particular, be considered as the plastic. One layer is,for example, a metal foil. The metal foil can also function assubstrate.

The partial quantity of the quantity of energy, which is accepted by alayer, depends for example on the absorption, emission and/or reflectioncapability of the layer. It also depends, however, on the type of theenergy source and on the way in which the quantity of energy istransmitted to the multilayer body or to a layer of the multilayer body.

One of the energy sources of the tempering unit is, for example, anenergy source for thermal energy. In this arrangement, the thermalenergy can be supplied direct to the layer. In this case, thermalradiation, thermal conduction and/or convection can be considered. Inthe case of the thermal radiation, the energy source itself can be asource for thermal radiation. The thermal radiation is, for example,electromagnetic radiation in the wavelength range between 0.7 and 4.5microns. The corresponding layer is arranged in the radiation field ofthe energy source. The layer is subjected to the electromagneticradiation of the energy source and absorbs, at least partially, theelectromagnetic radiation.

It is, however, also possible for any given energy, which is convertedinto thermal energy in the layer, to be supplied to a layer. As anexample, a layer is subjected to radiation by high-energy ultravioletlight which the layer absorbs. Due to an absorption of a high-energylight quantum, a molecule of the layer or the complete layer attains anelectronically excited state. Energy accepted in this process can beconverted into thermal energy.

In addition to thermal radiation and thermal conduction, tempering of alayer or the complete body is also possible by convection. In thisprocess, a gas with a certain energy is led past the layer, with the gasrejecting the energy to the layer. Gas which is led past cansimultaneously function as process gas.

Furthermore, the layer can also be cooled by thermal conduction and/orconvection. In this case, a negative thermal energy is supplied to thelayer. In this way, it is also possible to control the quantities ofenergy or the partial quantities of the energy quantities and, forexample, to additionally influence the mechanical stresses in themultilayer body.

In a particular embodiment, an energy transmitter for transmitting thequantity of energy onto the multilayer body is present. The energytransmitter functions as a secondary energy source. The energytransmitter absorbs, for example, electromagnetic radiation of a primaryenergy source, for example a halogen lamp, from a high energy range andconverts this electromagnetic radiation into thermal radiation, which isabsorbed by the layer.

The indirect and/or direct surroundings of the multilayer body canfunction as energy transmitter during the tempering process. It isconceivable for an energy transmitter to be arranged with the multilayerbody for tempering in an internal space of a tempering chamber. Theenergy transmitter can also be arranged outside the tempering container,for example on a wall of the tempering container or at a distance fromthe tempering container. It is conceivable for the energy transmitter tobe a coating of the tempering container. The energy transmitter is, forexample, a graphite foil. The tempering container can also itselfundertake the function of an energy transmitter. Such a function is, forexample, provided by a graphite tempering container. Finally, thetransparent body is nothing other than an energy transmitter. A gaslikewise functions as energy transmitter in the case of an energytransmission by convection.

An energy quantity which is accepted by the multilayer body can differnot only from layer to layer but also within a layer. As an example, anedge effect occurs in the multilayer body or in a layer of a multilayerbody during the tempering process. An edge region of the layer exhibitsa temperature different from that of an inner region of the layer. Alateral temperature gradient appears during tempering. This occurs, forexample, when a radiation field of the energy source is inhomogeneous.In this case, an energy density of the radiation field on a surface,through which the radiation radiates, is not the same everywhere. Alateral temperature inhomogeneity can also appear in the case of ahomogeneous radiation field if, at the edge of a layer, because of thelarger absorbing area per unit volume, a larger quantity of energy isabsorbed per unit volume. In order to even out the temperaturedifference, an energy source can, for example, be used which consists ofa number of sub-units. Each sub-unit can be separately triggered and, bythis means, each quantity of energy supplied from a sub-unit to a layercan be separately adjusted. Such an energy source is, for example, anarray or a matrix of individual heating elements. A heating element is,for example, a halogen lamp. The array or the matrix can also be used toproduce a lateral temperature gradient in the layer. In this way, it isfor example possible to specifically generate a permanent or transientdeformation of the layer body. In particular, an array or a matrix isvery advantageous for the tempering process of a multilayer body inwhich layers are located adjacent to one another.

With respect to the energy source, it is advantageous for the energysource or the energy sources to operate in continuous operation. It is,however, also conceivable for the energy sources to make available thequantity of energy or the partial quantities of the quantity of energyto the layers in a cyclic operation and/or pulse operation. Such anenergy source is, for example, an energy source with pulsedelectromagnetic radiation. In this way, a quantity of energy can besupplied to the layers at the same time or in a time sequence (forexample alternating).

The following properties of an energy source for electromagneticradiation are particularly advantageous:

The energy source exhibits a homogeneous radiation field.

A spectral intensity distribution of the energy source partiallyoverlaps a spectral absorption of the layer, of the transparent bodyand/or of a possibly present tempering container (see below).

In the presence of a process gas, the energy source is corrosionresistant and/or protected against corrosion.

The energy source exhibits a high energy density, which is sufficient toheat a mass of the multilayer body (and possibly of a temperingcontainer) at a heating rate of more than 1° C. per second.

In a particular embodiment, the transparent body of the applianceexhibits at least one distance holder, with which the multilayer body isin contact, for accepting a laterally homogeneous energy quantitythrough the multilayer body. As an example, the layer by means of whichthe multilayer body is in contact with the transparent body or thedistance holder is mainly tempered by a homogeneous thermal radiation.In this form, the distance holder preferably exhibits a material whichexhibits a low absorption for the electromagnetic radiation. A distanceholder protrudes, for example, beyond a surface of the transparent bodyby between some microns and up to millimeters.

The layer in contact with the distance holders can also be mainlytempered by thermal conduction. For this purpose, the distance holdershave available, for example, a thermal conductivity necessary for acorresponding tempering rate. It is also conceivable for the distanceholder to exhibit a high absorption for an electromagnetic radiation forthe energy transmission by thermal conduction, the electromagneticradiation being efficiently converted into thermal energy.

The transparent body exhibits, in particular, a number of distanceholders. In the case of a number of distance holders, which are arrangeduniformly in contact between the layer of the multilayer body and thetransparent body, a homogenization of the lateral temperaturedistribution can be additionally achieved.

In a particular embodiment, the transparent body and/or the distanceholder exhibits a material which is selected from the group of glassand/or glass ceramic. Glass ceramic exhibits various advantages:

It can be employed for tempering in a wide temperature range from, forexample, 0° C. to, for example, 700° C. Glass ceramic exhibits, forexample, a softening point which is located above the temperature range.

It has available a very low thermal expansion coefficient. It isresistant to temperature shock and is distortion-free in the temperaturerange, mentioned above, of the tempering process.

It is chemically inert with respect to a number of chemicals andexhibits a low permeability for these chemicals. Such a chemical is, forexample, the process gas, to which a layer and/or the completemultilayer body is exposed during the tempering process.

In the spectral range of many energy sources, it is optically partiallypermeable for electromagnetic radiation, in particular in a wavelengthrange in which the radiation density of the energy sources is high. Sucha radiation source is, for example, a halogen lamp with a high radiationdensity between 0.1 and 4.5 microns.

Glass, in particular quartz glass, is likewise conceivable as materialfor the transparent body. An advantageous feature here is a highemployment temperature of up to 1200° C. In the spectral range of anenergy source in the form of a halogen lamp, these materials exhibithigh transmission and low absorption. The light passes essentiallyunhindered through these transparent bodies and reaches a layer with acorresponding absorption for the electromagnetic radiation, the layeraccepting a quantity of energy and being heated. The transparent bodyremains practically unheated due to the radiation.

In a process application, it is possible for material of the heatedlayer to evaporate and be precipitated on a relatively cold surface ofthe transparent body. In order to prevent this, care can be taken toensure that the transparent body is heated to the necessary temperatureduring the tempering process. This is achieved by a transmission of aquantity of energy onto the transparent body by thermal conductionand/or convection. Also conceivable is an electromagnetic radiationwhich the transparent body absorbs. It is conceivable for thetransparent body to exhibit a coating which absorbs a certain part ofthe electromagnetic radiation. The energy accepted by this means can befed onto the glass or quartz glass transparent body. In this form, thetransparent body, consisting of the glass body with the coating, isoptically partially permeable and can be employed for energytransmission by both thermal radiation and thermal conduction onto themultilayer body.

In a particular embodiment, at least one layer of the multilayer body isin contact with a process gas. It is also conceivable for the completemultilayer body to be exposed to the process gas. An inert gas(molecular nitrogen or noble gas) can, for example, be considered asprocess gas. The process gas does not react with a material of thelayer. A process gas, which reacts with a material of the layer, ishowever also conceivable. The functional layer forms by the action ofthe process gas. The process gas acts, for example, in an oxidizing orreducing manner relative to a material of the layer. Possible processgases for this purpose are oxygen, chlorine, hydrogen, elementaryselenium, sulfur or a hybrid. It can also be an etching process gas suchas HCL or the like. Further examples of the process gas are H₂S andH₂Se, which are employed in the manufacture of a thin-film solar cell(see below). Finally, all gases or also gas mixtures which react in acorresponding manner with a material of a layer are conceivable.

It is advantageous for the layer to be exposed to a defined process gasatmosphere. The defined process gas atmosphere comprises, for example, apartial pressure of the process gas or process gases during thetempering process. It is also, for example, conceivable for a layer orthe multilayer body to be in contact with a vacuum for the temperingprocess.

A defined process gas atmosphere can, for example, be achieved by theprocess gas being led past the layer with a certain velocity. In thiscase, a process gas can act on the layer with different partialpressures in the course of the tempering process. It is also conceivablefor different process gases to be sequentially in contact with the layerof the layer body.

At least the layer which is in contact with the process gas ispreferably enclosed. This is, for example, achieved by a layer envelope,it being possible to fasten the envelope on the substrate. The envelopeis filled with the process gas before or during the tempering process.In this case, the process gas is concentrated on a surface of the layerwhose properties are to be influenced by the process gas. This canprevent surroundings being contaminated by the process gas. This isparticularly important in the case of a corrosive and/or poisonousprocess gas. In addition, it is possible to operate with astoichiometric quantity of process gas necessary for a conversion of thelayer. Process gas is not unnecessarily consumed.

In a particular embodiment of the invention, the multilayer body isarranged in a tempering container. In this arrangement, at least onecontainer wall of the tempering container exhibits a transparent body.The tempering container has the advantage that it automaticallyrepresents the envelope of the layer or of the complete multilayer body.The envelope does not need to be fastened to the multilayer body. In thecase of a tempering container which can be closed, the process gasatmosphere can be specifically and easily adjusted. The temperingcontainer offers, for example, a sufficiently large volume for theprocess gas required during the tempering process. If the temperingprocess demands a homogeneous and reproducible distribution of theprocess gas over a layer, a gas outlet from the tempering container canalso be specifically adjusted. This can, for example, be necessary whentempering takes place at a very high heating rate. In this case, theprocess gas expands. If the tempering container cannot withstand the gaspressure then occurring, a deformation of the tempering container oreven destruction of the tempering container occurs. A deformationshould, however, be prevented when, for example, the multilayer body isin contact with the bottom of the tempering container. A deformation ofthe tempering container can lead to a lateral temperature inhomogeneityin the multilayer body. The tempering container can additionally betransport means for the multilayer body during the tempering process.The tempering container has the advantage that during the temperingprocess, for example, a fracture of a glass layer (carrier layer orsubstrate)cannot be excluded. In the case of a fracture of such asubstrate, the broken material can be easily removed from the temperingunit or from the appliance for tempering. This contributes to temperingprocess stabilization.

In a particular embodiment, the container wall of the temperingcontainer, which exhibits the transparent body, is a cover and/or abottom of the tempering container. The multilayer body is located with alayer directly on the transparent body of the bottom, for example. Thetransparent body can, as described above, exhibit distance holders. Thecover likewise exhibits the transparent body which, for example, is notin contact with the multilayer body or a layer of the multilayer body.In this way, the layer of the multilayer body, which is in contact onthe bottom, can be heated by thermal conduction, the layer facing towardthe cover can be heated by thermal radiation. The layer facing towardthe cover can be easily exposed to a process gas.

In a further embodiment, the bottom and/or the cover of the temperingcontainer is respectively formed by at least one multilayer body. Inthis arrangement, the layer of the multilayer body, which has forexample to come into contact with the process gas, is directed into aninternal space of the tempering container. This solution is possible ifthe multilayer body or the layers of the multilayer body exhibit a lowthermal expansion coefficient and/or the tempering rate is small. In thecase of a high tempering rate, the multilayer body advantageously hasavailable a substrate with a high thermal conductivity coefficient. Thesubstrate is directed toward the outside. In this case, the substrateis, for example, a transparent body as described above.

In a particular embodiment, the tempering container, the transparentbody and/or the energy transmitter exhibits a material which is inertrelative to the process gas. It is also advantageous for the completeprocess surroundings of the tempering process to be inert relative tothe process gas used. The process surroundings also include, forexample, the energy source (primary energy source).

The material is selected as a function of the process gas. Glass, glassceramic and ceramic are, for example, conceivable. A fiber-reinforcedmaterial, such as carbon fiber reinforced graphite can likewise be used.Also conceivable is a material such as SiC, which exhibits a highthermal conductivity coefficient. The tempering container can consist ofa metal or an alloy. A plastic which can resist up to a certaintemperature is likewise possible.

In addition to chemical inertness relative to the process gas, thefollowing properties for the material of the tempering container are ofadvantage:

The material of the tempering container is distortion-free under thetempering conditions. It is, in addition, resistant to temperatureshock. This is particularly the case when it exhibits a lower thermalexpansion coefficient.

The thermal softening point of the material of the tempering containeris located above a maximum temperature of the tempering process.

The tempering container exhibits a low or defined permeability relativeto a process gas.

In a particular embodiment, a device is present for detecting a measureof at least one physical parameter, dependent on the tempering process,of the appliance and/or a tempering unit for regulating the first andsecond partial quantity of the quantity of energy.

A conceivable parameter is an absorption, transmission and/or reflectionproperty of a layer. The measure of the parameter is the value of theparameter. As an example, a wavelength of an absorption maximum candepend on the temperature. In this case, the measure of the parameterwould be the corresponding wavelength.

The parameter is, in particular, a temperature of the multilayer body.In this case, the measure is a value of the temperature. Alsoconceivable is the detection of the temperature of a layer of themultilayer body, of the transparent body and/or of the temperingcontainer or of a container wall of the tempering container. At leastone parameter of the multilayer body and/or of a layer can becontinuously detected during the tempering process. On the basis of thedetected temperature of a layer, for example, the partial quantity ofthe quantity of energy, which is accepted by the layer, is increased orlowered. By this means, a temperature inhomogeneity or a temperaturegradient in the thickness direction of the multilayer body can beavoided. This temperature inhomogeneity can also, however, be increasedif this should be necessary.

As an example, the device for detecting the temperature is be apyrometer which is directed onto the layer. The pyrometer detects, forexample, the thermal radiation which is emitted by the layer.Conclusions on the temperature of the layer can be drawn on the basis ofthe thermal radiation. Also conceivable is a temperature detector whichis connected to the layer and is tempered by thermal conduction.

It is also conceivable for the temperature of the layer or of themultilayer body not to be measured directly but to be measuredindirectly. As an example, a pyrometer is directed onto the temperingcontainer in which the multilayer body is tempered. The temperature ofthe tempering container can be influenced by the temperature of themultilayer body. Conclusions on the temperature of the layer of themultilayer body are drawn on the basis of the temperature of thetempering container. The quantity of energy or the partial quantity ofthe quantity of energy is regulated on the basis of the measuredtemperature of the tempering container. For this purpose, a sort of“calibration measurement” has to be carried out before the temperingoperation; this calibration provides a relationship between measuredtemperature of the tempering container and actual temperature of thelayer or of the layer body. The “calibration measurement” gives arequired value of the temperature. The actual value is detected. Acomparison between required value and actual value supplies. aregulation parameter for regulating the quantities of energy.

The detection (and also the regulation of the partial quantities of thequantity of energy) takes place, in particular, by means of a localresolution in the thickness direction of the multilayer body and bymeans of a time resolution in the time frame of the tempering process.As an example, the multilayer body is heated at a tempering rate of 25°C. per second. Both the detection and the regulation of the partialquantities of the quantity of energy would then take place so rapidlythat a temperature difference between the layers of the multilayer bodyremains, for example, below a specified maximum during the temperingprocess. In association with a transient deformation of the multilayerbody, the temperature inhomogeneity in the thickness direction can alsolead to a lateral temperature inhomogeneity in the multilayer body.Within a layer of the multilayer body, lateral signifies, for example,at right angles to the thickness direction. The multilayer body lies,for example, on a graphite bottom. The supply and the acceptance of thequantity of energy by the layer of the multilayer body incontact withthe bottom takes place by thermal conduction. A transient deformation ofthe multilayer body in the form of bending of the multilayer body canoccur due to a temperature inhomogeneity in the thickness direction. Inthis case, the contact between the multilayer body and the bottom of thetempering container, which is necessary for the thermal conduction, ispartially broken. As a consequence of this, a lateral temperatureinhomogeneity of the layer or of the multilayer body in contact takesplace. It is therefore particularly advantageous for a local resolutionto be present for the detection of the parameter (and regulation of thequantities of energy) not only in the thickness direction but alsolaterally.

In a particular embodiment, the parameter is a deformation of themultilayer body. A deformation can occur on the basis of a temperatureinhomogeneity which appears. The multilayer body is, for example, givena concave curvature. The multilayer body lies, for example, on thebottom of a tempering container. Due to the concave deformation, adistance between the contact surface and the multilayer body occurs inthe edge region of the multilayer body. A measure of such a deformationcan, for example, be detected by means of a device for laserinterferometry or laser light reflection. The regulation of thequantities of energy takes place on the basis of the measure. It isadvantageous for the measure to be recognized at an early stage of thedeformation and to be rapidly reacted to.

For a device, as discussed, for the detection of a measure of aparameter dependent on the tempering process with the aid of an opticaldevice (for example laser), it is advantageous for the layer to beinvestigated to be accessible to light of the optical device and for adetection signal to be unambiguously associated with the parameter to bedetected. The wavelength of a laser should, for example, differsufficiently from the thermal radiation of the multilayer body. If theappliance is equipped with a tempering container, it would beadvantageous for the transparent body to be sufficiently permeable tothe light of the laser.

Using the appliance, it is also possible to achieve a desireddeformation of the multilayer body. For this purpose, it can be sensibleto follow the deformation, as described above, during the temperingprocess. It is, for example, possible to produce a curved thin-filmsolar cell. For the desired deformation, the multilayer body is laid,for example, on a corresponding mold or mask. The mold or mask can be adirect energy source. The multilayer body is heated beyond a softeningpoint of the substrate. As a result of this, the multilayer body takeson a shape corresponding to the mask or the mold. The mask isintegrated, for example, in a bottom of the tempering container. Themask could, for example, be the transparent body.

In order to achieve the object, a method is provided, in addition to theappliance, for tempering a process item and at least one further processitem while using the appliance described. The method exhibits thefollowing method steps: a) arranging the tempering unit with the processitem and the further tempering unit with the further process item toform the tempering stack and b) tempering the process item and thefurther process item.

In particular, the tempering process comprises at least one heatingprocedure and/or at least one cooling procedure of the process itemand/or of the further process item. It is, for example, conceivable fora plurality of heating phases and a plurality of cooling phases to bepassed through during the tempering process. The method is thenparticularly suitable for carrying out the tempering of the processitems under a process gas atmosphere. For this purpose, the firstprocess item and/or the further process item is brought into contactwith at least one process gas. It/they can be brought into contactbefore, during or after the tempering process. In this case, one of theprocess items can be brought into contact simultaneously with aplurality of process gases (gas mixture). It is also conceivable for theprocess item to be brought into contact in sequence with various processgases and/or scavenging gases. This permits a variable process gasprofile (time sequence of different partial pressures of the process gasor process gases). In this way, it is for example possible to employboth oxidizing and reducing process gases or to specifically introduce adoping material into the process item.

In a particular embodiment, the following process steps are provided: c)arranging the tempering stack in a hollow space of a stack body, d)arranging the stack body in a tempering chamber at a distance from thetempering chamber, so that an intermediate space occurs between thestack body and the tempering chamber, and e) producing a gas pressure ofa scavenging gas in the intermediate space. These process steps takeplace before the tempering process. The intermediate space with thescavenging gas functions as a buffer so that the process gas, which islocated in the hollow space, does not reach the tempering chamber oronly reaches it when diluted. Contamination or corrosion of thetempering chamber can be prevented. The selection of the material of thetempering chamber is almost independent of the process gas. Theintermediate space can be filled once with scavenging gas. It is alsoconceivable for a continuous scavenging gas flow to be led through theintermediate space, which scavenging gas flow is possibly removed fromthe process gas emerging, from the intermediate space, from the stackbody. Removal of emerging process gas is also achieved because apressure drop is generated from the hollow space of the stack body tothe intermediate space. In a particular embodiment, a gas pressure of ascavenging gas is generated in the intermediate space between temperingchamber and stack body, which gas pressure is larger than the gaspressure in the hollow space of the stack body. For this purpose, gasoutlet openings are preferably provided in the stack body, which, forexample, are led to the outside via a collecting tube conduit throughthe intermediate space and through the tempering chamber and are thereled, for example, into a gas removal unit. The pressure, which is alsopresent in the gas removal unit (for example atmospheric pressure) istherefore approximately present in the hollow space of the stack body.The effect of this arrangement can be designated as gap counterflowscavenging, which is used to retain an inert gas counterflow against theprocess gas flow which is diffusing out at a gap of a lead-through ofthe stack body, for example at an envelope of an energy source, or at ajoint gap of a component of the stack body. The objective of this is toprevent a condensation of process gases on the tempering chamber wallsor a corrosion of the tempering chamber walls. The latter can, in anycase, also be achieved by a suitable coating of the tempering chamberwalls.

The gap counterflow scavenging takes place in accordance with thefollowing principle. The tempering containers filled with the processgas are arranged in the stack body. The possibility cannot be excludedthat the process gas may pass into the hollow space of the stack body.The hollow space of the stack body and the intermediate space betweenstack body and tempering chamber are in connection through small gaps oropenings. A pressure gradient from the intermediate space to the hollowspace of the stack body is built up by the selection of the gaspressures. This, for example, takes place by extracting the scavenginggas of the hollow space and/or introduction of the scavenging gas intothe intermediate space and a pressure build-up, caused by this, relativeto the pressure of the hollow space which, as described above can be incontact with the surroundings of the appliance of the tempering process.As a result, there is a scavenging gas flow from the intermediate spaceto the hollow space. The process gas does not reach the chamber wall ofthe tempering chamber. By this means, in particular, a tempering chambertemperature, the gas pressure of the hollow space and/or the gaspressure of the intermediate space are adjusted during the temperingprocess.In a particular embodiment, a multilayer body with a layer andat least one further layer is used as process item and/or furtherprocess item. In this case, the tempering process takes place byacceptance of a quantity of energy by the multilayer body with anacceptance of a first partial quantity of the quantity of energy by thefirst layer and an acceptance of a second partial quantity of thequantity of energy by the second layer, at least one energy source beingused to supply the quantity of energy to the multilayer body. In thisprocess, an appliance previously described is, in particular, used. Themethod steps are: arranging the multilayer body between a first and atleast one second energy source, so that the first layer is arrangedbetween the first energy source and the second layer and the secondlayer is arranged between the second energy source and the first layer,at least one energy source for a certain electromagnetic radiation witha radiation field being used as the energy source, and at least one ofthe layers absorbing the electromagnetic field and being arranged in theradiation field of the energy source, and arrangement of a transparentbody in the radiation field of the energy source between the energysource and the layer, which is located in the radiation field of theenergy source and which absorbs the certain electromagnetic radiationand tempering of the multilayer body.

In a particular embodiment, the transparent body absorbs a certainquantity of energy and supplies the quantity of energy to the layer. Ina further embodiment, detection of a measure, dependent on the temperingprocess, of a physical parameter of the multilayer body is carried outduring the tempering process in order to regulate the acceptance of thequantity of energy during the tempering process and to regulate thefirst and second partial quantities of the quantity of energy. In aparticular embodiment, the transparent body supplies the quantity ofenergy to the layer by thermal conduction and/or thermal radiation.

In a particular embodiment, a multilayer body is used with a layer whichexhibits copper, indium, gallium and/or selenium. A multilayer bodywith, in particular, a substrate in glass and/or metal is used. Thesubstrate can, for its part, exhibit a coating (for example a metallayer on a glass plate). A gas, which is selected from the group of H₂S,H₂Se, H₂, He and N₂, is used as the process gas. The method is usedparticularly for producing a photovoltaic thin-layer chalcopyriteabsorber of a solar cell and/or a solar module. A number of individualsolar cells connected in series is present in the solar module. Theglass is preferably soda lime glass. The corresponding layer functionsas substrate. On the substrate, a molybdenum layer as electrode and,over the molybdenum layer, a functional layer, namely acopper-indium-galium-sulpho-selenide (CIGSSe) semiconductor layer, isapplied. A thickness of the layer body, consisting glass body andsemiconductor layer is typically between 2 and 4 mm, with a molybdenumlayer of approximately 0.5 microns and a semiconductor layer ofapproximately 3 microns. The range given for the thickness of themultilayer body does not have to be used exclusively. The limitingfactor is a capability of manufacturing a large substrate which is, asfar as possible, plane and, therefore, can be processed to a multilayerbody with the appliance described and with the method described.

Summarizing, the invention provides the following advantages:

A plurality of process item can be tempered simultaneously underchanging process gas atmosphere. In the process, a heating profileand/or cooling profile of the tempering process can be variablyconfigured.

A process item in the form of a large-area multilayer body with anasymmetrical layer build-up (for example multilayer body with a singlelayer on a substrate) can be tempered at a high tempering rate of morethan 1° C. per second.

The layers of the multilayer body can, in this system, exhibit a greatlydiffering thermal conductivity coefficient and/or a greatly differingemission capability.

By means of a resolution in time and location of the detection and theregulation of a measure of a parameter dependent on the temperingprocess, tempering can be achieved particularly reliably. As an example,it is possible to react to a change in a property of the process item(for example emission or absorption capability) during the temperingprocess and, thereupon, to adjust the process parameters (pressure,temperature, energy density, etc).

Tempering to near a softening point of a substrate is possible.

Rapid tempering of between 1° C. per second and up to 100° C. per secondis possible. In this process, temperatures of, for example, 1100° C. canbe achieved.

When tempering beyond the softening point of the substrate, permanentdeformation of the multilayer body is possible.

Defined tempering surroundings with a defined process gas atmosphere canbe created. Different process gases with different partial pressureprofiles can be adjusted simultaneously or sequentially before, duringand/or after the processing. A toxic and/or corrosive process gas can,in particular, be employed. Condensation of a process substance on thechamber walls can be avoided.

All method steps necessary for the processing can be carried out with asingle appliance.

BRIEF DESCRIPTION OF THE DRAWINGS

Using a plurality of embodiment examples and the associated figures, anappliance for tempering a process item and a corresponding method forthis are presented. The figures are diagrammatic and do not representtrue-to-scale illustrations.

FIG. 1 shows, from the side, a cross section through an appliance fortempering at least one process item.

FIGS. 2a to 2 f show possible embodiments of the tempering unit.

FIG. 3 shows an excerpt from the tempering stack, the process items oftwo tempering units being connected together by means of passageopenings.

FIG. 4 shows a closed stack body which can be evacuated and can befilled with gas.

FIG. 5 shows a stack body, which is arranged in a tempering chamberwhich can be evacuated.

FIGS. 6a to 6 c show an energy source, which is arranged in an envelope.

FIGS. 7a to 7 c show various embodiments of the reflection body.

FIG. 8 shows a cross section through a certain appliance for tempering.

FIG. 9 shows a longitudinal section through the certain appliance fortempering.

FIG. 10 shows an excerpt from the longitudinal section of the certainappliance for tempering.

FIG. 11 shows a method for tempering a plurality of process items.

FIG. 12 shows a cross section through an embodiment for processing aplurality of process items while emphasizing the principle of the gascounterflow scavenging.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The starting point is an appliance 1 for tempering a plurality ofprocess items 33 and 43 (FIG. 1). The appliance consists of a pluralityof tempering units 3 and 4 arranged one above the other to form atempering stack 2. A tempering unit 3 and 4, respectively, exhibits anenergy source 32 and 42, respectively. In order to temper the processitems, the energy sources and the process items are arranged on oneanother in such a way that, in a certain stack direction 22 of thetempering stack 2, the process item 33 is arranged between the energysource 32 and the further energy source 42 and the further energy source42 is arranged between the process item 33 and the further process item43.

The energy sources 32 and 42 are, in one configuration, rod-shapedhalogen lamps 61, which are arranged in the form of an array 64 (FIG.6). Each of the halogen lamps 61 of the array 64 is arranged in a quartzglass envelope 60.

The intermediate space between envelope 60 and halogen lamp 61 has,flowing through it, a liquid or gaseous coolant 62. During the temperingprocess, the halogen lamps 61 emit an electromagnetic radiation 34 or 44in the form of infrared radiation, which is absorbed by the processitems 33 and 43 in order to accept a corresponding quantity of energy.For this purpose, the process items 33 and 43 are arranged in theradiation fields of the energy sources 32 and 42. In a first embodiment,the process item 33 of a tempering unit 3 is only exposed to theradiation field 34 of the energy source 32 of the tempering unit 3 (FIG.2a). In a further embodiment, the process item 33 is additionallyarranged in the radiation field 44 of the energy source 42 of anadjacent tempering unit 4 (FIG. 1). In a next embodiment, a reflectionbody 5 is arranged so as to form the radiation field (FIG. 2b). Thereflection body 5 consists of an aluminum oxide coating 501 on a glassceramic substrate 502 (FIG. 7a). The reflection body 5 reflectselectromagnetic radiation 341, which meets the aluminum oxide coating501, in the direction of the corresponding process item 33.

Two further solutions for the configuration of the reflection body 5 areshown in FIGS. 7b and 7 c. The reflection body 52 is, as shown in FIG.7b, a part of the envelope 60 of the energy source 61. From FIG. 7c, thereflection body 53 is arranged directly on a quartz glass envelope ofthe halogen lamp 61.

In a further configuration, the reflection body 5 is partially permeableto the electromagnetic radiation 34 so that a part of the radiation 342is given up in an adjacent half space (FIG. 2b).

In one embodiment, the envelopes 60 are open at both ends (FIG. 6b). Forcooling purposes, a coolant 62 in the form of a cooling gas is pumpedthrough the envelope 60. In a further embodiment, the envelope 60 issupplemented by a covering 66 (FIG. 6c). The intermediate spacegenerated by this between the covering 66 and the envelope 60 isprovided with supply and drain 67 and a cooling fluid 65 flows throughit for cooling purposes.

As shown in FIG. 2c, the tempering unit has available an additionalenergy source 7 with an additional electromagnetic radiation 71, towhich the process item 33 is exposed. From FIG. 2d, a transparent body 8and 9 are respectively arranged in the radiation fields of the energysource 32 and the additional energy source 7. The transparent bodies 8and 9 are glass ceramic plates, which are semitransparent to theelectromagnetic radiation 34 and the additional electromagneticradiation 71. The process item 33 lies on one transparent body 8. A partof the electromagnetic radiation 71 is absorbed by this transparent body8 and is led on to the process item 33 in the form of thermal conduction81.

Further embodiments may be seen in FIGS. 2e and 2 f. From FIG. 2e, thetempering unit 3 exhibits an open tempering container 10 in which theprocess item 33 is arranged. A container wall 101 of the temperingcontainer 10 exhibits a transparent body 8. The container wall 101 isthe bottom of the tempering container 10. The tempering container 10 canbe closed, according to the embodiment of FIG. 2f. The temperingcontainer 10 has closable openings (gas openings) 11 available forevacuating and filling the tempering container 10 with process gas,which openings are configured as valves. As an alternative to this, thevalves are self-closing (non-return valves).

FIG. 3 shows one possibility for jointly exposing the temperingcontainer 10 of two tempering units 3 and 4 to the process gas 12. Inthis arrangement, the tempering containers 10 are connected together bymeans of the gas inlets and outlets 35, 36, 45 and 46. In anotherembodiment, each tempering container is separately filled with processgas 12.

FIG. 4 shows a tempering stack 2, whose stack walls are partially formedby the body walls of the stack body 21. Additional walls are provided byreflection bodies 5 in the form of reflection plates (FIG. 7a). In afurther embodiment, this tempering stack 2 is arranged at a distance 303in a tempering chamber 31 which can be evacuated (FIG. 5).

A particular embodiment is shown in the FIGS. 8 to 10. Each of thetempering units 3 and 4 of the tempering stack 2 is built up in such away as is represented in FIG. 2d, none of the tempering units 3 and 4having an additional energy source 7. The energy sources 32 and 42 arearrays 64 of rod-shaped halogen lamps 61. The upper and lowertermination of the tempering stack 2 respectively forms a plate-shapedreflection body 5 with array 64 of halogen lamps 61, arranged toward thetempering stack 2, as energy source. The transparent bodies 8, 9 in theform of glass ceramic plates are pushed into grooves in the stack body21.

One tempering container 10 is formed from two transparent bodies 8 and 9and the body wall of the stack body 21. The tempering container 10 hasavailable openings 11 for producing a certain gas atmosphere in thetempering containers 3 and 4.

FIG. 12 shows an excerpt from FIG. 8 in order to emphasize the gapcounterflow scavenging. A pressure gradient or a gas flow 13 resultingfrom this is indicated by the arrows. During the tempering process, agas atmosphere 50 of the process gas 12 at a certain gas pressure 103 ispresent in a container inlet space 102 of a tempering container 10. Theprocess gas 12 can emerge into the hollow space 301 of the stack body 21through a gap 104 of the tempering container 10. In order to prevent thechamber wall within the tempering chamber 31 being contaminated by theprocess gas 12, the hollow space 301 is connected to surroundings 14 inwhich is present a gas pressure 141 which is smaller than the gaspressure 103 in the container internal space 102 of the temperingchamber 31. At the same time, this ensures that a gas pressure 304,which corresponds approximately to the gas pressure 103 which is presentin the container internal space 102 of the tempering container 10, ispresent in the intermediate space 302 between the chamber wall of thetempering chamber 31 and the body wall of the stack body 21. It issomewhat larger so that the process gas 12 does not pass through a gap202 of the stack body 21 into the intermediate space 302. Because thegas pressure 141, which is smaller in comparison to the pressures 103and 304, is present in the surroundings 14, process gas 12 possiblypresent in the hollow space 301 of the stack body 21 is transported inthe direction of the surroundings 14 because of the pressure gradientspresent. In the case of toxic process gases or vapors, these are removedby intermediately connected removal units such, for example, as wetwashing units or cooling traps. Only carrier gases which areunproblematic are then, for example, released into the surroundings 14.

The stack body 21 is inserted in a tempering chamber 31. The stack body21 has available a door 201 which can be opened independently of thedoor 311 of the tempering chamber 31. The door simultaneously representsa container wall of the tempering container.

The following procedure of a method for the tempering process is givenas an example:

Loading the stack body with the process items (111)

Closing the tempering chamber.

Multiple pumping out and filling of the tempering chamber with inert gaswith the stack body open.

Closing the stack body and, by this means, closing the temperingchamber.

Opening the scavenging gas inlet and outlet for gap counterflowscavenging.

Opening the process gas inlet and outlet into the tempering containerand carrying out the desired process gas partial pressure profile.

Adjusting a low cooling air flow through the envelopes of the energysources.

Tempering (112): switching on the energy sources and regulating theheating array in accordance with a desired temperature profile.Regulation input parameter is the signal from thermal elements, whichare applied, in one embodiment, to the tempering containers 10.

Switching on or regulating down the energy sources 32, 42 and 7 andcontrol of the cooling profile by regulating the cooling air flow.

Introducing a scavenging gas into the process gas inlets.

Opening the stack body and multiple pumping down and filling with inertgas.

Opening the tempering chamber and unloading the process item.

In one embodiment, an upper heating and lower heating of a process itemis separately triggered during the tempering process. This, however, isonly possible with energy sources which can be separately triggered andbetween which the process item is located. The following alternativesolutions exist for the case where one energy source is provided in thetempering stack for one process item and where, during the temperingprocess, a fixed adjustment of the ratio between upper heat and lowerheat can be tolerated:

Bottom and cover of the tempering container 10 consist of differentinfrared-permeable material. The cover

is in glass ceramic which partially absorbs infrared. The bottomexhibits a graphite. In another embodiment, the cover is in quartz glassand the bottom in ceramic.

Bottom and cover of the tempering container consist of the same materialbut have a different optical density with respect to the infraredradiation and different thicknesses of bottom and cover.

The energy sources are coated on one side with infrared partialreflectors.

The envelopes are coated on one side with infrared partial reflectors.

Use of reflection bodies between the tempering units.

What is claimed is:
 1. An appliance for tempering a plurality of processitems in a certain gas atmosphere by acceptance of a quantity of energyby a process item by means of absorption of a certain electromagneticradiation and by acceptance of at least a further quantity of energy byat least one further process item by means of absorption of at least afurther certain electromagnetic radiation, wherein the appliancecomprises: a first tempering unit and at least one further temperingunit arranged parallel to each other to form a stack extending in astack direction between a first termination of the stack and a secondtermination of the stack, wherein each said tempering unit includes anenergy source for generating the electromagnetic radiation and, duringtempering, a process item arranged between the energy source of thefirst tempering unit and the energy source of the further tempering unitin the stack direction, and wherein the second termination of the stackis formed by an energy source, and, during tempering, a further processitem arranged between the energy source of the tempering unit adjacentto the second termination and the energy source of the secondtermination.
 2. The appliance as claimed in claim 1, wherein at leastone of the tempering units comprises at least one additional energysource for generating an additional quantity of energy and for gettingthe additional quantity of energy accepted by the process item of thetempering unit.
 3. The appliance as claimed in claim 1, wherein at leastone of the tempering units comprises at least one reflection body forforming a radiation field of at least one of the electromagneticradiations.
 4. The appliance as claimed in claim 1, wherein the firsttermination of the stack is formed by a reflection body.
 5. Theappliance as claimed in claim 1, wherein the second termination of thestack further comprises a reflection body.
 6. The appliance as claimedin claim 1, wherein the first termination of the stack is formed by areflection body, and wherein the second termination of the stack furthercomprises a reflection body.
 7. The appliance as claimed in claim 3,wherein the reflection body comprises a material which at leastpartially reflects the electromagnetic radiation of the energy source.8. The appliance as claimed in claim 1, wherein at least one of thetempering units further includes means for cooling the process item. 9.The appliance as claimed in claim 1, wherein at least one of the energysources is arranged in an envelope, which is at least partiallytransparent to the electromagnetic radiation of the respective energysource.
 10. The appliance as claimed in claim 9, further comprisingmeans for passing a cooling fluid through the envelope of the energysource.
 11. The appliance as claimed in claim 9, wherein the envelope ofthe energy source includes a reflection body.
 12. The appliance asclaimed in claim 1, wherein at least one said tempering unit includes atempering container, for holding the process item of the tempering unit,which tempering container comprises a container wall.
 13. The applianceas claimed in claim 1, wherein the tempering stack forms a stack bodywith a body wall.
 14. The appliance as claimed in claim 1, furthercomprising a tempering chamber having a chamber wall, in which chamberduring normal operation the stack is arranged.
 15. The appliance asclaimed in claim 13, further comprising a tempering chamber having achamber wall, in which chamber during normal operation the stack body isarranged.
 16. The appliance as claimed in claim 15, wherein at least oneof the stack body and the tempering chamber is tempered.
 17. Theappliance as claimed in claim 15, wherein the tempering chamber isprovided with a vacuum-tight door, on which, inside the temperingchamber, a door of the stack body is arranged, wherein a door of thestack body can be opened and closed independently of a door of thetempering chamber.
 18. The appliance as claimed in claim 12, wherein thecontainer wall comprises means for producing the gas atmosphere.
 19. Theappliance as claimed in claim 13, wherein the body wall comprises meansfor producing the gas atmosphere.
 20. The appliance as claimed in claim14, wherein the chamber wall comprises means for producing the gasatmosphere.
 21. The appliance as claimed in claim 18, wherein the meansis a gas opening for at least one gas for evacuating and/or filling thetempering container with the gas.
 22. The appliance as claimed in claim1, wherein at least one of the process items is a multilayer body withat least one layer which exhibits a certain absorption for theelectromagnetic radiation.
 23. The appliance as claimed in claim 1,wherein at least one of the tempering units further includes atransparent body that exhibits a certain absorption and a certaintransmission for the electromagnetic radiation and which is arranged inthe radiation field of the electromagnetic radiation between the energysource of the electromagnetic radiation and one of the process items.24. The appliance as claimed in claim 23, wherein the transparent bodycomprises a material which is inert with respect to the gas.
 25. Amethod of tempering a process item and at least one further process itemwhile using an appliance as claimed in claim 1, comprising steps of: a)arranging the tempering unit with the process item and the furthertempering unit with the further process item to form the temperingstack; and b) tempering the process item and the further process item.26. The method as claimed in claim 25, in which the process item and/orthe further process item are brought into contact with at least oneprocess gas.
 27. The method as claimed in claim 25, further comprisingthe steps of: c) arranging the tempering stack in a hollow space of astack body; d) arranging the stack body in a tempering chamber at adistance from the tempering chamber, so that an intermediate spaceoccurs between the stack body and the tempering chamber; and e)producing a gas pressure of a scavenging gas in the intermediate space.28. The method as claimed in claim 27, wherein a gas pressure of ascavenging gas is generated in the intermediate space between temperingchamber and the stack body, which gas pressure is larger than the gaspressure in the hollow space of the stack body.
 29. The method asclaimed in claim 28, wherein a connection is produced by an opening,between the intermediate space and the hollow space, in such a way thata pressure gradient can be set between. the hollow space and theintermediate space.
 30. The method as claimed in claim 25, in which amultilayer body with a layer and at least one further layer is used asprocess item and/or further process item.
 31. The method as claimed inclaim 25 for producing a photovoltaic thin-layer chalcopyrite absorberof a solar cell and/or a solar module.